I have been working for the past few months on a Planescape campaign world conversion for Fantasy Craft (a few forum members are helping as well). One of the things I had to do in order to convert AD&D (Advanced Dungeons & Dragons) monsters to Mastercraft was to write a conversion manual. Well, I am pleased to share it with you here. This is an excerpt from a much larger book which covers the whole Planescape setting. Since the big book isn't finished yet, I thought some of you guys/girls might find it useful. I have already converted hundreds of monsters with it.

P.S. Personally, I feel that conversion from AD&D works better than those from d20 because it follows more closely "the Crafty concept of monster making". The d20 versions of monsters tend to be overloaded with options which makes them more challenging to use in the game.

Very cool. I am curious why you decided to flatten out Intelligence, since AD&D follows a pretty hard 3-18 range, just as FC does. Compared to some by-the-book 3e conversions, Intelligence might be a little higher.

I didn't suggest to convert it directly because AD&D scores are already directly translated into d20 (see Conversion Manual here http://www.wizards.com/default.asp?x=dnd/er/20030221a). Then you have Fantasy Craft which says that you shouldn't convert d20 stats directly but adjust them (e.g. Intelligence 18 [+4] becomes 14). In my conversion manual, I'm just skipping the d20 part so it might seem like a big difference between those two numbers. Most converted AD&D monsters should end up with same Intelligence scores as if they have been converted from d20. If that's not the case, there's always "Step 9: Final Tweaks" for any additional adjustments

See, in d20, you would have like an angel or dragon or something with Int 21. That would turn into FC Int 15, rounding down to 14. But look at the fire dragon with its Int of 14; in AD&D a red dragon rates as Exceptional, while in d20 it would have an Int of 14 to 18 in the Huge size category. Even though using the AD&D intelligence score might result in slightly higher scores in some areas, I think it's closer. Anything over 18 represents an unnaturally high ability.

You should refer to Table 3.1: Descriptive Intelligence Conversion only if you're converting from AD&D 1st edition. That table is there only if you don't know what those scores really are. I haven't made them up - when you look at 2nd edition, you will notice that they defined Godlike Intelligence as 21+. Not that high really. I should probably put a whole 21 to 25 range in there so Godlike would turn into a 16 - 18 range. (or just maybe 16+)

Are you suggesting that we should make an exception for Intelligence scores above 18 and convert them directly?

P.S. I wrote earlier that "I'm just skipping the d20 part so it might seem like a big difference between those two numbers." Actually, what I meant was that I was fast-forwarding over the d20 part

Neat guide, and good to know my work on monster conversion continues to inspire A poorly kept secret is that I use FC to run old AD&D/BD&D modules for friends - it's a ball!

One thing I should note, however, is that you need to include an OGL declaration at the end of your document - otherwise, technically this is copyright infringement. You can find the basic document for our stuff in text here, and be sure to add a section for Fantasy Craft from the OGL declaration at the end of FC.